This application claims the priority of German Patent Document 101 60 748.2, filed on Dec. 11, 2002, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a motor vehicle having a front end comprising an air guiding device which has a pneumatic operating element in order to operatively displace the air guiding device from an inoperative position into an operative position.
A motor vehicle of the above-mentioned type is known from German Patent Document DE 31 45 257 C2. It has a front end on which an air guiding device is fastened which has a pneumatic operating element in order to displace the air guiding device from an inoperative position into a moved-out operative position. The pneumatic element simultaneously forms the spoiler element and is therefore implemented as an inflatable hollow body which, in the inflated condition, guides the air on the vehicle such that, at higher speeds, the wheel adhesion is to be increased and simultaneously the drag coefficient of the vehicle is to be reduced. When the inflated hollow body is to be moved into the inoperative position, it is evacuated by air suction. This known vehicle has the disadvantage that the hollow body may be damaged during the drive.
An aspect of the invention is to provide a motor vehicle of the initially mentioned type whose air guiding device has a longer service life.
This aspect can be achieved in that the air guiding device has a spoiler lip comprising a flexible and elastic material, wherein the pneumatic operating element is constructed as an inflatable hose arranged, viewed in a driving direction, behind the spoiler lip and wherein the elastic spoiler lip rests in the inoperative position under prestress against the front end. Additional characteristics further developing the invention are described below and in further embodiments.
Principal advantages achieved by certain preferred embodiments of the invention are that, as a result of the spoiler lip being arranged in front of the pneumatic operating element and displaced into the operative position, the pneumatic operating element is Protected from stones and from damage when driving over an object as the motor vehicle is driven. Also in the moved-in position or inoperative position of the air guiding device, the pneumatic operating element is covered by the elastic spoiler lip so that here also a protection is provided, for example, against accumulating dirt. As a result of that, in the inoperative position, the flexible and elastic spoiler lip is prestressed and in the process is placed against the front end or is placed almost against the front end, it is further prestressed or stretched when it is moved out, whereby a restoring force is built up and, when the hose is relieved from pressure, a automatic restoring of the spoiler lip occurs into the inoperative position. In addition, it is advantageous that, as a result of the prestressing, the spoiler lip is securely held in the inoperative position and therefore does not flutter during the drive.
As a further development, the hose has at least two chambers which are arranged above one another and which, viewed against the driving direction, are arranged offset with respect to one another. Thus, it is advantageous that, in the operative position, an aerodynamically advantageous contour is impressed on the spoiler lip.
In addition or as an alternative, according to a further development, the hose, viewed in cross-section, has a drop-shaped, oval, or circular construction, and thus the aerodynamic contour of the spoiler lip can be further influenced. If several chambers are provided, these may be constructed in a drop shape wherein at least one of the chambers, viewed in cross-section, has a drop-shaped, oval, or circular construction. The hose and the chambers, respectively, as an alternative, may have an oval or approximately circular cross-section.
In an embodiment the chambers, viewed in cross-section, have different sizes. The different size of the chambers may have an influence on the aerodynamic contour of the spoiler lip in the operative position.
A particularly favorable aerodynamic contour of the spoiler lip can be achieved in that the chamber situated adjacent to the spoiler lip has the smallest cross-section. Another alternative for the shaping of the spoiler lip in the operative position is that the chamber situated adjacent to the front end has the largest cross-section.
In an embodiment in which the chambers have a mutual air connection, it is advantageous that all chambers can be supplied by an air source. An alternative, in which each of the chambers is separately supplied with air, is advantageous in that, when one chamber is not tight, the other operable chambers can be activated, so that an emergency operation of the air guiding device can take place by way of the intact chambers.
In order to provide the air guiding device with a higher stability in the operative position, the chambers are fastened to one another or have a material lengthening by means of which they are held on the underside of the front end.
A particularly preferred embodiment in which, viewed in a transverse direction of the vehicle, the spoiler lip has mutually spaced ventilation openings for supplying air to the wheel brakes, and thus an overheating of the forward wheel brakes is avoided by providing ventilation openings in the spoiler lip.
The reinforcing of the ventilation openings in their edge area provides the spoiler lip with a high stiffness in the operative position.
A restoring of the spoiler lip displaced in the operative position is promoted by a further development wherein at a free end, the spoiler lip has a pocket in which a bending-elastic element is arranged which extends approximately along the entire width of the front end and which can be displaced in the pocket in a transverse direction of the vehicle. The bending-elastic element arranged in the pocket also stiffens the spoiler lip in the operative position and supports the spoiler lip in the area below the ventilation openings, in which area the hose or the chambers can be recessed.
According to a further development wherein the front end has a recess which extends along the width of the front end and, in which, the hose and the spoiler lip are situated in the inoperative position, the spoiler lip is lowered into a recess of the front end so that it does not impair the clearance of the vehicle above the road surface in the area of the front end.
The spoiler lip made of the elastic material was found to be particularly advantageous in the case of a front end which, viewed in the driving direction, is curved out. The elastic spoiler lip can easily adapt itself to the curved shape.
An embodiment wherein the air guiding device can be displaced as a function of a driving speed of the motor vehicle into the operative position and back into the inoperative position, and vice-versa, is preferable in which case, as a function of the driving speed of the motor vehicle, the spoiler lip is displaced into the operative position or is displaced back from the operative position into the inoperative position. Particularly, at low speeds, the spoiler lip will be in the inoperative position so that, for example, during the parking of the motor vehicle, a damaging of the spoiler lip on the curb is avoided.
An embodiment is provided for constructing the spoiler lip and the hose or the chambers in one piece, and thus form a prefabricated module, whereby a simple manufacturing of the air guiding device is permitted. In addition, when the one-piece air guiding device is moved, no friction occurs between the spoiler lip and the pneumatic element.
In a further development wherein the hose and/or at least one of the chambers, viewed in a transverse direction of the vehicle, is constructed to be elastically flexible and to be substantially inflexible in cross-section. Therefore, it is advantageous that the hose, which is elastically flexible in the transverse direction of the vehicle, can adapt itself to the curved or bent shape of the front end so that the hose can uniformly support the spoiler lip and can provide additional restoring force in the operative position. With respect to the cross-section, the hose or the chamber cannot be stretched, whereby the aerodynamic contour impressed on the spoiler lip by the cross-sectional shape of the hose is not influenced.
According to a preferred embodiment wherein a protective element for the pneumatic element extends between a rearward side of the spoiler lip and an underside of the front end, the pneumatic element is protected from dirt and damage.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.